Java IsNullValue.isDefinitelyNotNull方法代码示例

import edu.umd.cs.findbugs.ba.npe.IsNullValue; //导入方法依赖的package包/类
/**
 * Clear deref sets of values if this edge is the non-null branch of an if
 * comparison.
 *
 * @param fact
 *            a datflow fact
 * @param edge
 *            edge to check
 * @return possibly-modified dataflow fact
 */
private @CheckForNull
ValueNumber findValueKnownNonnullOnBranch(UnconditionalValueDerefSet fact, Edge edge) {

    IsNullValueFrame invFrame = invDataflow.getResultFact(edge.getSource());
    if (!invFrame.isValid()) {
        return null;
    }
    IsNullConditionDecision decision = invFrame.getDecision();
    if (decision == null) {
        return null;
    }

    IsNullValue inv = decision.getDecision(edge.getType());
    if (inv == null || !inv.isDefinitelyNotNull()) {
        return null;
    }
    ValueNumber value = decision.getValue();
    if (DEBUG) {
        System.out.println("Value number " + value + " is known nonnull on " + edge);
    }

    return value;
}
 

import edu.umd.cs.findbugs.ba.npe.IsNullValue; //导入方法依赖的package包/类
public static boolean reportPotentialDereference(Location location, IsNullValueFrame invFrame)
        throws DataflowAnalysisException {
    if (!invFrame.isValid())
        return false;
    IsNullValue value = invFrame.getTopValue();
    if (value.isDefinitelyNotNull())
        return false;
    if (value.isDefinitelyNull())
        return false;
    return true;
}
 

import edu.umd.cs.findbugs.ba.npe.IsNullValue; //导入方法依赖的package包/类
private static boolean reportDereference(IsNullValue value) {
    if (value.isDefinitelyNotNull())
        return false;
    if (value.isDefinitelyNull())
        return false;
    if (IGNORE_DEREF_OF_NCP && value.isNullOnComplicatedPath())
        return false;
    return true;
}
 

import edu.umd.cs.findbugs.ba.npe.IsNullValue; //导入方法依赖的package包/类
public boolean ignoreExceptionEdge(Edge edge, Lock resource, ConstantPoolGen cpg) {

            try {
                Location location = cfg.getExceptionThrowerLocation(edge);
                if (DEBUG) {
                    System.out.println("Exception thrower location: " + location);
                }
                Instruction ins = location.getHandle().getInstruction();

                if (ins instanceof GETFIELD) {
                    GETFIELD insGetfield = (GETFIELD) ins;
                    String fieldName = insGetfield.getFieldName(cpg);
                    if (DEBUG) {
                        System.out.println("Inspecting GETFIELD of " + fieldName + " at " + location);
                    }
                    // Ignore exceptions from getfield instructions where the
                    // object reference is known not to be null
                    if (fieldName.equals("lock"))
                        return true;
                    IsNullValueFrame frame = isNullDataflow.getFactAtLocation(location);
                    if (!frame.isValid())
                        return false;
                    IsNullValue receiver = frame.getInstance(ins, cpg);
                    boolean notNull = receiver.isDefinitelyNotNull();
                    if (DEBUG && notNull) {
                        System.out.println("Ignoring exception from non-null GETFIELD");
                    }
                    return notNull;
                } else if (ins instanceof InvokeInstruction) {
                    InvokeInstruction iins = (InvokeInstruction) ins;
                    String methodName = iins.getMethodName(cpg);
                    // System.out.println("Method " + methodName);
                    if (methodName.startsWith("access$"))
                        return true;
                    if (methodName.equals("readLock") || methodName.equals("writeLock"))
                        return true;
                    if (methodName.equals("lock") || methodName.equals("unlock"))
                        return true;
                }
                if (DEBUG) {
                    System.out.println("FOUND Exception thrower at: " + location);
                }
            } catch (DataflowAnalysisException e) {
                AnalysisContext.logError("Error while looking for exception edge", e);
            }

            return false;
        }